Description : Armature cores in a DC generator are made of laminated steel sheets to _____________. A. fit the curvature of the frame B. increase the hysteresis effect C. reduce eddy current losses D. allow for easy assembly
Last Answer : Answer: C
Description : 43 The purpose of providing an iron core in a transformer is to A.Provide support to windings B. Reduce hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses
Last Answer : C. Decrease the reluctance of the magnetic path
Description : 8 The transformer core is laminated to A. Reduce the copper losses B. Reduce the core losses C. Reduce the eddy current losses D. None of the above
Last Answer : C. Reduce the eddy current losses
Description : 19 Transformer cores are built up from laminations rather than from solid metal so that A. Oil penetrates the core more easily B. Eddy current loss is reduced C. Less lamination is required for the windings D. Turn ratio is higher than voltage ratio
Last Answer : B. Eddy current loss is reduced
Description : 9 Which loss is not common between a transformer and rotating machines? A. Eddy current loss B. Copper loss C. Windage loss D. Hysteresis loss
Last Answer : A. Eddy current loss
Description : 17. Which type of loss is not common to transformer and rotating machines? A. Eddy current loss B. Copper loss C. Hysteresis loss D. Windage loss
Last Answer : D. Windage loss
Description : A transformer at 25 Hz develops 20 W hysteresis loss and 50 W eddy current loss. If the applied voltage and frequency are doubled, the new core losses are (A) 140 W (B) 180 W (C) 240 W (D) 480 W
Last Answer : A transformer at 25 Hz develops 20 W hysteresis loss and 50 W eddy current loss. If the applied voltage and frequency are doubled, the new core losses are 240 W
Description : Transformer cores are laminated to reduce _____________. A. eddy currents B. secondary flux C. leakage flux D. all of the above
Last Answer : Answer: A
Description : The armature of a dc machine is laminated to reduce: (A) Eddy current loss (B) Hysteresis loss (C) copper losses (D) friction and windage losses
Last Answer : Ans: A Thinner the laminations, greater is the resistance offered to the induced e.m.f., smaller the current and hence lesser the I2R loss in the core.
Description : 69 In case there are burrs on the edges of the laminations of the transformer, it is likely to result in A. Vibrations B. Noise C. Higher eddy currents loss D. Higher hysteresis loss
Last Answer : C. Higher eddy currents loss
Description : Eddy current losses in transformer cores can be reduced by the use of 1. Solid cores 2. Laminated cores 3. Ferrites Select the correct answer using the codes given below : (a) 2 and 3 only (b). 1 and 2 only (c) 1 and 3 only (d) 1, 2 and 3
Last Answer : Eddy current losses in transformer cores can be reduced by the use of 1. Solid cores 2. Laminated cores 3. Ferrites Select the correct answer using the codes given below : (a) 2 and 3 only (b). 1 and 2 only (c) 1 and 3 only (d) 1, 2 and 3
Description : 42 The efficiency of a transformer will be maximum when A. copper losses = hysteresis losses B. Hysteresis losses = eddy current losses C. Eddy current losses = copper losses D. Copper losses = iron losses
Last Answer : D. Copper losses = iron losses
Description : The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction
Description : 70] Silicon steel used in laminations mainly reduces A. Hysteresis loss B. Eddy current losses C. Copper loss D. All of the above
Last Answer : A. Hysteresis loss
Description : 7 The main advantage of auto transformer over a two winding transformer is A. Hysteresis losses are reduced B. Saving in winding material C. Copper losses are negligible D. Eddy losses are totally eliminated
Last Answer : A) hysteresis losses is reduced
Description : 71 High frequency transformers sometimes make use of ferrite cores because it has A. High specific gravity B. High resistance C. High hysteresis D. low permeability
Last Answer : B. High resistance
Description : What is Eddy current loss in transformer?
Last Answer : In transformer, we supply alternating current in the primary, this alternating current produces alternating magnetizing flux in the core and as this flux links with secondary winding, there will be induced ... dissipated as heat. This type of energy loss is called eddy current loss of transformer.
Description : What is hysteresis loss in transformer?
Last Answer : The magneto motive force or mmf applied in the transformer core is alternating. For every cycle due to this domain reversal, there will be extra work done. For this reason, there will be a consumption of electrical energy which is known as Hysteresis loss of transformer.
Description : Which of the following properties is not necessarily desirable in the material for transformer core? A. Mechanical strength B. Low hysteresis loss C. High thermal conductivity D. High permeability
Last Answer : C) high thermal conductivity
Description : A 220/440 V, 50 Hz, 5 KVA, single phase transformer operates on 220V, 40Hz supply with secondary winding open circuited. Then (A) Both eddy current and hysteresis losses decreases. (B) Both ... same but hysteresis loss increases. (D) Eddy current loss increases but hysteresis loss remains the same.
Last Answer : (A) Both eddy current and hysteresis losses decreases.
Description : Why does the core of a transformer need to be laminated?
Last Answer : Transformer cores are laminated to reduce eddy current loss.
Last Answer : Transformer core is laminated to reduce Eddy current losses.
Description : How can eddy current loss be minimized?
Last Answer : By laminating the core.
Description : How do we minimize eddy current loss?
Last Answer : A. By laminating the core we can minimize eddy current loss.
Description : How to minimize Eddy current loss?
Last Answer : By using less thickness of laminations By using less value of Magnetic flux density
Description : Transformer cores are laminated with (A) Low carbon steel. (B) Silicon sheet steel. (C) Nickel alloy steel. (D) Chromium sheet steel.
Last Answer : (B) Silicon sheet steel.
Description : Laminated cores, in electrical machines, are used to reduce?
Last Answer : Laminated cores, in electrical machines, are used to reduce eddy current loss.
Description : The hysteresis and eddy current losses of a single phase transformer working on 200 V, 50 Hz supply are Ph and Pe respectively. The percentage decrease in these when operated on a 160 V, 40 Hz supply are (a) 32, 36 (b) 20, 36 (c) 25, 50 (d) 40, 80
Last Answer : The hysteresis and eddy current losses of a single phase transformer working on 200 V, 50 Hz supply are Ph and Pe respectively. The percentage decrease in these when operated on a 160 V, 40 Hz supply are 20, 36
Description : Mention the factors on which hysteresis loss depends?
Last Answer : (i) Quality and amount of iron in the core (ii) Flux density and (iii) Frequency.
Description : How to minimize Hysteresis loss?
Last Answer : By using good magnetic material. By using less value of Magnetic flux density
Description : Which of the following losses is/are present in every direct current generator armature? A. Winding copper loss B. Core eddy current loss C. Magnetic hysteresis loss D. All of the above.
Last Answer : Answer: D
Description : As an armature revolves within a magnetic field, friction is developed between the rotated magnetized particles as they pass through each magnetization cycle. This results in ____________. A. copper loss B. eddy-current loss C. hysteresis loss D. armature reaction
Description : A ferrite core has less eddy current loss than an iron core because ferrites have (A) High resistance. (B) Low resistance. (C) Low permeability. (D) High hysteresis.
Last Answer : (A) High resistance.
Description : What is the difference between eddy current and hysteresis loss?
Last Answer : Loss occurred by magnetising and demagnetising process is called histerisis loss and the current flowed due to the magnetic field produced by the electric field applied is called eddy current losses
Description : Explain hysteresis loss, eddy current loss and skin effect limitations with reference to magnetic material.
Last Answer : Hysteresis loss: Hysteresis loss is a loss which occurs due to the friction of magnetic domain due to the change in magnetic field in ferromagnetic material like iron. Hysteresis loss causes power loss ... loss in transformer is given by, We=Kef2Kf2Bm2watts Skin effect limitations:
Description : Why stepped cores are used?
Last Answer : (i) To reduce the space effectively. (ii) To obtain reduced length of mean turn of the windings. (iii) To reduce I² R loss.
Description : 40 No load test on a transformer is carried out to find A. Copper loss B. magnetising current C. Magnetising current and loss D. Efficiency of the transformer
Last Answer : C. Magnetising current and loss
Description : 22 No load test on a transformer is carried out to find A. copper loss B. magnetising current C. Magnetising current and no load loss D. Efficiency of the transformer
Last Answer : C. Magnetising current and no load loss
Description : Where is core type and shell type construction suitable for a transformer?
Last Answer : Core type transformers are popular in High voltage applications like Distribution transformers, Power transformers, and obviously auto transformers. Where as, Shell type transformers are ... voltage applications like transformers used in electronic circuits and power electronic converters etc
Description : Material used for construction of transformer core is usually A. 0.4mm to 0.5 mm B. 4mm to 5 mm C. 14mm to 15 mm D. 25mm to 40 mm
Last Answer : d) 25mm to 40mm
Description : Explain construction and working of single phase Auto transformer.
Last Answer : Construction of single phase auto transformer: (i) It has only one winding wound on a laminated circular magnetic core. (ii) The core is made of silicon steel stampings. (iii) The two terminals of the ... help of handle. 5) The same transformer can be used as step-up or step down auto-transformer
Description : Explain construction and working principle of single phase transformer.
Last Answer : A single phase transformers is an electrical device that accepts single-phase AC power and outputs single-phase AC. PRINCIPLE... The single-phase transformer works on the principle of ... and secondary windings. Thin steel laminations shall be employed to prevent power losses from the core.
Description : Explain construction and working of isolation transformer.
Last Answer : Isolation Transformer https://youtu.be/gq9kjLlhPN0
Description : The core construction is like spokes of a wheel in following transformer: (A) Berry Type Transformer (B) Core Type Transformer (C) Shell Type Transformer (D) None of the above
Last Answer : The core construction is like spokes of a wheel in following transformer: Berry Type Transformer
Last Answer : Material used for construction of transformer core is usually silicon steel.
Description : 45 The function of conservator in a transformer is A. To protect against internal fault B. To reduce copper as well as core losses C. To cool the transformer oil D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings
Last Answer : D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings
Description : A transformer operates 24 hours day at full -load. It's full -load efficiency is : (A) equal all day efficiency (B) more than all -day efficiency (C) less than all -day efficiency (D) equal to maximum efficiency
Last Answer : A transformer operates 24 hours day at full -load. It's full -load efficiency is : equal all day efficiency
Description : Eddy current damping is an example of _____ A Coulomb damping B Hysteresis damping C Viscous damping D Dry friction damping
Last Answer : C Viscous damping
Description : Eddy current damping is an example of _____A. Coulomb damping B. Hysteresis damping C. Viscous damping D. Dry friction damping
Last Answer : C. Viscous damping